I have an 07 unlimited x automatic. I do not have the tow package, though, which comes with 4.10's i believe. I think I have the S package??? maybe. Its got 17 inch wheels, premium sound, cruise, power windows, power locks, premium sound, side airbags, tow hooks front and rear, running boards, leather wrapped steering wheel, and fog lights. Anyways I am running superchips and when I pulled up the gear ratio it defaulted with 4.10's? I am hoping that it pulled that info from the ECU. Anyone running superchips can confirm this for me? I never really thought my Jeep was all that "sluggish" but I can't really compare. I am really hoping I have the 4.10's

 

To verify what gears you have, you can call your local Jeep dealership, and give them the last 8 of your VIN. They will look up the factory info for you.

 

Looking at the '07 Owners Manual, all the '07 JK's with automatic transmission came with 4.10 gears.

If you bought it used, a previous owner may have re-geared it.

 

Yea, I bought it used, everything else is stock though so I am thinking they are 4.10's...maybe I should crack the owner's manual open sometime

 

To calculate your gear ratio. Jack up the rear end, block the wheels and put the transmission in neutral and see how many times you have to turn the driveshaft to get one tire rotation. 3 turns = 3.21. 4 turns = 4.1; etc.

 

I quit publicly posting instructions on this because nobody seems to want to do it.
People today seem to want the indirect information from a build sheet.

 

I appreciate the info and replies.

Found this for the 2007 JK
http://www.offroaders.com/tech/jeep/...r-JK-SPECS.htm

Transmission:

42RLE—Automatic, Four-Speed Overdrive

Availability Optional
Description Electronic governor, electronically controlled converter clutch
Gear Ratios 1st 2.84
Gear Ratios 2nd 1.57
Gear Ratios 3rd 1.0
Gear Ratios 4th 0.69
Gear Ratios Reverse 2.21
Axle Ratio 4.10
Overall Top Gear 2.83

 

Cameron1022,


Check your PM inbox.

 

I've been trying to find out what gears I have in my 07 unlimited. I bought the Jeep used. Best I can guess is that the tow package installed at the dealership. Would they have changed out the gears at the dealership? Regardless, still looking to find out what's actually installed.

If I were to lift the back end... can you just turn the drive staff by hand? Sorry for the noob question. Is this the easiest way to finding out?

Any help would be greatly appreciated.

 

Factory Tow package upgrades ratio to 3.73